文档介绍：第一节不等式和绝对值不等式 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 三年 16考高考指数:★★★ ,并能利用含绝对值不等式的几何意义证明以下不等式: ①|a+b| ≤|a|+|b|; ②|a-b| ≤|a-c|+|c-b|. :|ax+b| ≤c;|ax+b| ≥c;|x-a|+|x-b| ≥c. Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 、基本不等式证明一些简单问题;能够利用基本不等式求一些特定函数的最(极)值. Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 、比较实数的大小、,也是难点. ,属低、中档题. Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. a>b b<a ? a>b,b>c a>c ? a>b a+c>b+c ? a>b,c>0 ac>bc ①? a>b,c<0 ac<bc ②? a>b>0 a n>b n(n∈N,n ≥2) ? a>b>0 (n ∈N,n ≥2) ? n n a b ? Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 【即时应用】(1) 思考:若 a<b,一定有吗? 提示:: a=-1,b=2 时,有 a<b,但事实上,当 ab>0时,若 a<b,则有当ab<0时,若 a<b,则有当ab=0 时,若 a<b,则中有一个无意义. 1 1 a b > 1 1 . a b > 1 1 ; a b > 1 1 ; a b < 1 1 a b 和 Evaluation only. Evaluation only. Created with Client Profile . Created with